<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      body {
        display: table;
        /* word-spacing: ; */
      }
      .header {
        width: 600px;
        height: 50px;
        background-color: red;
      }
      .lc {
        width: 300px;
        height: 300px;
        display: inline-block;
        /* margin: 0; */
        background-color: rgba(0, 0, 255, 0.2);
      }
      .rc {
        width: 300px;
        height: 300px;
        display: inline-block;
        /* margin: -2em; */
        background-color: yellow;
      }
      .di {
        width: 600px;
        height: 50px;
        background-color: green;
      }
    </style>
  </head>
  <body>
    <div class="header"></div>
    <div class="lc"></div>
    <div class="rc"></div><!--
    --><div class="di"></div>
  </body>
</html>
